The armored workhorse of the US Army, the M113 has been on the move since Vietnam

By: Carl O. Schuster January 16

U.S. soldiers on M113 armored vehicles take part during the Warrior Strike VIII exercise at the Rodriguez Range on Sept. 19, 2017, in Pocheon, South Korea. (Chung Sung-Jun/Getty Images)

A group of troops atop an M113 is one of the iconic images of the Vietnam War. The M113 armored personnel carrier, second only to the UH-1 Iroquois “Huey” helicopter in battlefield importance, entered production in April 1960. Developed by FMC, the aluminum-hulled M113, intended to be amphibious and air transportable, was considerably lighter than its predecessor, the M59.

Unfortunately, its limited freeboard (distance from the water line to the roof) of 14 inches precluded use in amphibious operations. But the M113 could cross rivers with slow currents, relying on its hydraulically tensioned tracks for propulsion.

Initially propelled by a 260 horsepower Chrysler 75M V-8 gasoline engine, the M113 was soon eclipsed by the diesel-powered M113A1, introduced in April 1963. By July 1, 1968, many M113s in Vietnam were diesel-powered.

The M113A1 was configured for a two-man crew — a commander/gunner and driver — and 11 other soldiers. It included a hydraulically operated rear ramp for rapid exit. The ramp also had a hatch for access when it was up. The driver had four M17 periscopes, and his hatch could mount an M19 infrared periscope for night movements.

File photo: Vietnamese combat engineers have invented a new protection device against anti-tank rockets (B 40 and B 50 rockets) for the American made M113 Armored Personnel Carrier: a wire mesh is attached to the sides of the carrier. The wire mesh prevents the rocket from reaching the aluminum (cq) hull of the carrier --which it would otherwise easily penetrate. The new device was shown to President Tieu during a military show on Oct. 3, 1968 at Pleiku, central Vietnamese highlands. (AP Photo/Lo Vinh)

Combat experience led the troops to alter many standard features. Units removed the track shrouds and mud flaps to make track repairs faster. They also took out the commander’s and driver’s seats, placing C-ration crates in their cupolas for seating. They added extensions to the driver’s steering levers so he could operate from atop the vehicle. And they replaced the troops’ compartment seats with wooden benches and stored ammunition underneath them.

Other enhancements included protective steel plates welded to the commander’s cupola or the .50-caliber M2 machine gun mount. Additionally, most units mounted one or two M60 machine guns next to the roof cargo hatch. Over time, the improvised armor protecting the machine gunners evolved into rotating gun shields providing all-around protection. They were standard equipment by 1970, designated as armored cavalry assault vehicle kits.

Largely replaced by the M2 Bradley infantry fighting vehicle in the 1980s, the M113A1 and related variants continue to serve with America’s allies and military partners.